SIGNL4

SIGNL4 is a mobile alerting and on-call duty management service that transforms emails, webhooks, and IoT events into reliable push, SMS, and voice alerts with acknowledgement tracking, escalation, and team on-call scheduling. The platform provides both an inbound webhook for sending alerts and a REST API for managing alerts, statuses, annotations, and team data. Authentication uses a team or webhook secret embedded in the URL path or supplied via the X-S4-Api-Key header.

SIGNL4 publishes 4 API contracts indexed on the APIs.io network, including Events API, Webhook API, and 2 more. Tagged areas include Alerting, Incident Management, On-Call, Mobile Alerts, and Notification.

The SIGNL4 catalog on APIs.io includes 1 Spectral governance ruleset.

SIGNL4’s developer surface includes authentication, documentation, pricing, signup flow, support, engineering blog, GitHub presence, and 6 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

36.0/100 thin ▬ flat Agent 19/100 agent aware Front door AI 4/6 moderate Heartbeat 100/100 alive saas Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

1 published contract

Alerting Incident Management On-CallMobile AlertsNotification DevOps IT Operations Monitoring

What this lets a business do 1

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

SaaS Platform Operations Management

BC-4220

Events

POST /api/v2/events/{webhookIdOrTeamId}

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 36.0/100 · thin

Contract Quality 10.1 / 19

Developer Ergonomics 5.4 / 15

Access Clarity 3.8 / 15

Operational Transparency 0.5 / 10

Contract Governance 1.2 / 9

Discoverability 5.0 / 8

Regulatory Posture 1.6 / 15

Create-or-Update Ergonomics 2.8 / 10

Agent readiness — 19/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship Ask about this →
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented) Ask about this →
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented) Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →

9 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 25.5 — up to +14.9 composite points Ask about this →
Developer Ergonomics scores 35.7 — up to +12.9 composite points Ask about this →
Operational Transparency scores 4.8 — up to +12.4 composite points Ask about this →

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/signl4/apis.yml: open an issue on github.com/api-evangelist/signl4 to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Atlassian Marketplace (builders on Jira, Confluence, Bitbucket)	builds-on	51.8	-	-
APIs.guru OpenAPI Directory (API definition directory)	builds-on	51.8	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 1

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

APIs 4

Individual APIs this provider publishes, each with its own machine-readable definition.

SIGNL4 Inbound Webhook API

Simple HTTPS webhook endpoint for triggering mobile alerts in SIGNL4 from any monitoring, ITSM, or IoT tool. Accepts JSON payloads with Title and Message fields plus optional X-...

SIGNL4 REST API

RESTful API for programmatic alert lifecycle management including creating events, acknowledging or closing alerts, annotating alerts, and retrieving team data. Authentication i...

SIGNL4 Events API

The Events API from SIGNL4 — 1 operation(s) for events.

SIGNL4 Webhook API

The Webhook API from SIGNL4 — 1 operation(s) for webhook.

Open Collections 3

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

SIGNL4 Webhook and REST Events API

OPEN COLLECTION

SIGNL4 and REST Events Webhook API

OPEN COLLECTION

SIGNL4 Webhook and REST API

OPEN COLLECTION

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

SIGNL4 API Rules

52 rules · 50 error-severity 1 warn-severity 1 info-severity

SPECTRAL

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

SIGNL4 Authentication

apiKey · 1 scheme

SECURITY

SIGNL4 Domain Security

TLSv1.3 · DMARC

SECURITY

SIGNL4 Trust Center

ISO 27001, GDPR

SECURITY

Agentic Access (API Evangelist recommendations) 1

Recommended x-agentic-access execution contracts for AI agents.

SIGNL4 Agentic Access

2 operations · 2 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

Signup

Signup

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHub

GitHub

Access & Security 3

Authentication, authorization, and security posture

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 1

Pricing, plans, and the legal terms of use

Pricing

Pricing

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Source (apis.yml)

aid: signl4
name: SIGNL4
description: SIGNL4 is a mobile alerting and on-call duty management service that transforms emails, webhooks, and IoT events
  into reliable push, SMS, and voice alerts with acknowledgement tracking, escalation, and team on-call scheduling. The platform
  provides both an inbound webhook for sending alerts and a REST API for managing alerts, statuses, annotations, and team
  data. Authentication uses a team or webhook secret embedded in the URL path or supplied via the X-S4-Api-Key header.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/signl4.png
tags:
- Alerting
- Incident Management
- On-Call
- Mobile Alerts
- Notification
- DevOps
- IT Operations
- Monitoring
tags_raw:
- Alerting
- Incident Management
- On-Call
- Mobile Alerts
- Notifications
- DevOps
- IT Operations
- Monitoring
url: https://raw.githubusercontent.com/api-evangelist/signl4/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-11'
specificationVersion: '0.23'
apis:
- aid: signl4:inbound-webhook
  name: SIGNL4 Inbound Webhook API
  description: Simple HTTPS webhook endpoint for triggering mobile alerts in SIGNL4 from any monitoring, ITSM, or IoT tool.
    Accepts JSON payloads with Title and Message fields plus optional X-S4 control parameters for service categorization,
    location, alerting scenario, and external identifiers. Authentication uses a unique team or webhook secret embedded in
    the URL path.
  humanURL: https://docs.signl4.com/integrations/webhook/webhook.html
  baseURL: https://connect.signl4.com/webhook
  tags:
  - Webhook
  - Inbound
  - Alerting
  - Mobile Push
  properties:
  - type: Documentation
    url: https://docs.signl4.com/integrations/webhook/webhook.html
  - type: APIReference
    url: https://connect.signl4.com/webhook/docs/index.html
  - type: CodeExamples
    url: https://github.com/signl4/code-snippets
- aid: signl4:rest-api
  name: SIGNL4 REST API
  description: RESTful API for programmatic alert lifecycle management including creating events, acknowledging or closing
    alerts, annotating alerts, and retrieving team data. Authentication is via X-S4-Api-Key header with the team or webhook
    secret.
  humanURL: https://docs.signl4.com/integrations/rest-api/rest-api.html
  baseURL: https://connect.signl4.com/api
  tags:
  - REST
  - Alert Management
  - Event
  - Incident Response
  tags_raw:
  - REST
  - Alert Management
  - Events
  - Incident Response
  properties:
  - type: Documentation
    url: https://docs.signl4.com/integrations/rest-api/rest-api.html
  - type: Overview
    url: https://www.signl4.com/webhook-rest-smtp-api-integration/
  - type: CodeExamples
    url: https://docs.signl4.com/samples/code-samples/code-samples.html
- aid: signl4:signl4-events-api
  name: SIGNL4 Events API
  description: The Events API from SIGNL4 — 1 operation(s) for events.
  humanURL: https://docs.signl4.com/integrations/webhook/webhook.html
  baseURL: https://connect.signl4.com/webhook
  tags:
  - Event
  tags_raw:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/signl4-events-api-openapi.yml
- aid: signl4:signl4-webhook-api
  name: SIGNL4 Webhook API
  description: The Webhook API from SIGNL4 — 1 operation(s) for webhook.
  humanURL: https://docs.signl4.com/integrations/webhook/webhook.html
  baseURL: https://connect.signl4.com/webhook
  tags:
  - Webhook
  properties:
  - type: OpenAPI
    url: openapi/signl4-webhook-api-openapi.yml
common:
- type: CapabilityMap
  url: capabilities/signl4-capability-edges.yml
  name: SIGNL4 Business Capability Map
- type: AgenticAccess
  url: agentic-access/signl4-agentic-access.yml
- type: TrustCenter
  url: security/signl4-trust-center.yml
- type: DomainSecurity
  url: security/signl4-domain-security.yml
- type: Authentication
  url: authentication/signl4-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/signl4
- type: Website
  url: https://www.signl4.com
- type: Documentation
  url: https://docs.signl4.com
- type: Pricing
  url: https://www.signl4.com/pricing/
- type: Signup
  url: https://account.signl4.com/register
- type: Support
  url: https://support.signl4.com
- type: Blog
  url: https://www.signl4.com/blog/
- type: GitHub
  url: https://github.com/signl4
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

SIGNL4 API — frequently asked questions

Does SIGNL4 have an API?

Yes. APIs.io lists 4 APIs from SIGNL4, including SIGNL4 Inbound Webhook API, SIGNL4 REST API and SIGNL4 Events API, and 1 more.

Is there an OpenAPI specification for the SIGNL4 API?

Yes. APIs.io indexes 2 OpenAPI specifications for SIGNL4, each linked for download from this page.

How do I authenticate with the SIGNL4 API?

SIGNL4 uses bearer-token authentication (apiKey · 1 scheme). The details are profiled on APIs.io as SIGNL4 Authentication.

Is the SIGNL4 API ready for AI agents?

SIGNL4 has a Kin Score of 36.0 out of 100 (thin) and an Agent Readiness score of 18.5 (agent-aware), scored by API Evangelist on 2026-11-13.

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